Using vibrational Cooper minima to determine strong-field molecular-dissociation pathways*

We explore the possibility of using vibrational ``Cooper minima'' (VCM) locations as a method to determine dissociation pathways of molecules in a strong laser field. As a test case, we study the laser-induced dissociation of an O$_2^+$ ion beam by several wavelengths ($\lambda = 800$, 400, and 266 nm) using a coincidence three-dimensional momentum imaging technique. Vibrational structure is observed in the kinetic energy release spectra, revealing a suppression of the dissociation of certain vibrational levels, which is a manifestation of the VCM effect. Previously, it has been shown in H$_2^+$ that first-order time-dependent perturbation theory can be used to predict the locations of the VCM [1]. We explore if the VCM locations predicted by perturbation theory can help uniquely identify dissociation pathways in O$_2^+$ and consider its utility for other systems. \\[4pt] [1] J. McKenna et. al., Phys. Rev. Lett. 103, 103006 (2009).